This invention relates to test patterns for use in testing the quality of a lens and more in particular to a vernier resolution chart and a triangular-wave pattern for testing of a camera lens.
The method preferred in the prior art for testing camera lenses is the direct measurement of the modulation transfer function (mtf) using specialized electronic instruments as in "Electro-Optical Methods of Image Evaluation", Baker, L. R., and T. Moss, Electro-Optical Systems Design Conference, New York City, 1969. Photographic methods for making similar measurements are less accurate, and usually require the use of a microdensitometer. An attempt to circumvent this limitation is that described in "The Sharpness Indicator", I. Putora, J. of the SMPTE, 78: pp. 956-960, November 1969 who photographs circular test patterns of varying fineness with high contrast film; the lens resolution is determined directly by inspection of the negative. Described herein are different improved test patterns which provide direct indication of lens performance when photographed with high contrast film.